Information recording medium, method and apparatus for recording and reproducing information

ABSTRACT

An information recording medium includes a lead-in area and a data area for storing contents information. The lead-in area includes a first lead-in information area and a second lead-in information area. The first lead-in information area corresponds to a first playback mode. The second lead-in information area corresponds to a second playback mode different from the first playback mode. The first lead-in information area has a first depth and is designed for storing lead-in information related to the contents information stored in the data area. The second lead-in information area includes pre-pits having a second depth greater than the first depth. The pre-pits represent predetermined information, such as information of copyright protection, related to the contents information stored in the data area.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to an information recording medium.

Also, this invention relates to a method and an apparatus for recordinginformation on a recording medium. In addition, this invention relatesto a method and an apparatus for reproducing information from arecording medium.

2. Description of the Related Art

A DVD (digital versatile disc) family contains a DVD-Video and a DVD-RW.Here, DVD-RW is short for DVD-Rewritable.

The DVD-Video is designed for a playback purpose (a reproductionpurpose) only. In general, the DVD-Video stores main information, andcopyright information corresponding to the main information. Forexample, the copyright information is designed to prevent the contentsof the main information from being illegally copied. According to a CSS(a contents scramble system), the copyright information is recorded on agiven area of the disc, that is, an area of the disc which is assignedto information related to copyright protection such as information of aCSS key.

A DVD-Video player operates as follows. First, the player reads outinformation of a CSS key from a disc. When the information of the CSSkey is correct, the player is permitted to reproduce the contents ofmain information from the disc. Otherwise, the player is inhibited formreproducing the contents of the main information. Thus, the CSS keyfunctions to prevent the contents of the main information from beingillegally copied.

It is assumed that a DVD recording system illegally records DVD-Videocontents information and corresponding CSS-key information on a disc. Inthis case, since the correct CSS-key information is present in the disc,a DVD-Video player can reproduce the DVD-Video contents information.Thus, in this case, it is difficult to protect copyright on theDVD-Video contents information.

The DVD family also contains a DVD-R (a DVD-Recordable). Information canbe recorded on the DVD-R only once. It is conceivable that before theshipment of a virgin DVD-R from a factory, the disc is physicallyprocessed to record a special code signal other than a signal of a CSSkey on a given area of the disc which corresponds to a copyrightinformation area of a DVD-Video. In this case, it is difficult to writeinformation of a CSS key over the given area of the DVD-R after theshipment thereof from the factory. It is assumed that a DVD recordingsystem illegally records DVD-Video contents information on such a DVD-R.CSS-key information corresponding to the DVD-Video contents informationis absent from the DVD-R since it is difficult to record the CSS-keyinformation on the disc. Accordingly, in this case, a DVD-Video playercan not reproduce the DVD-contents information from the disc. Thus, itis possible to protect copyright on the DVD-Video contents information.

The DVD-RW has the feature that information can be repetitively recordedthereon a plurality of times. An explanation is now given of the casewhere before the shipment of a virgin DVD-RW from a factory, a specialcode signal other than a signal of a CSS key is recorded on a given areaof the disc which corresponds to a copyright information area of aDVD-Video. Even in this case, it is possible for a DVD recording systemto illegally record DVD-Video contents information and correspondingCSS-key information on the DVD-RW after the shipment thereof from thefactory. Since the correct CSS-key information is present in the disc, aDVD-Video player can reproduce the DVD-Video contents informationtherefrom. Thus, in this case, it is difficult to protect copyright onthe DVD-Video contents information.

Regarding a DVD-RW or a similar rewritable disc storing DVD-contentsinformation permitted to be copied, it is desirable that theDVD-contents information can be reproduced from the disc. Also, in somecases, it is desirable that the DVD-contents information can be copied.

An optical disc conforming to the RTR (real-time recording) standards isincompatible with a DVD-Video. Regarding an RTR disc storing maininformation and copyright information, it is desirable to control thecopying (the recording and the reproduction) of the main information inaccordance with the contents of the copyright information.

SUMMARY OF THE INVENTION

It is a first object of this invention to provide an improvedinformation recording medium.

It is a second object of this invention to provide an improved method ofrecording information on a recording medium.

It is a third object of this invention to provide an improved apparatusfor recording information on a recording medium.

It is a fourth object of this invention to provide an improved method ofreproducing information from a recording medium.

It is a fifth object of this invention to provide an improved apparatusfor reproducing information from a recording medium.

A first aspect of this invention provides an information recordingmedium comprising a lead-in area and a data area for storing contentsinformation, the lead-in area including a first lead-in information areaand a second lead-in information area, the first lead-in informationarea corresponding to a first playback mode, the second lead-ininformation area corresponding to a second playback mode different fromthe first playback mode, the first lead-in information area having afirst depth and being for storing lead-in information related to thecontents information stored in the data area, the second lead-ininformation area including pre-pits having a second depth greater thanthe first depth, the pre-pits representing predetermined informationrelated to the contents information stored in the data area.

A second aspect of this invention provides an information recordingmedium comprising a lead-in area and a data area for storing contentsinformation, the lead-in area including a first lead-in information areaand a second lead-in information area, the first lead-in informationarea corresponding to a first recording/playback mode, the secondlead-in information area corresponding to a second recording/playbackmode different from the first recording/playback mode, the first lead-ininformation area being for storing lead-in information related to thecontents information stored in the data area in units of predeterminederror correction blocks, the second lead-in information area being forinerasably storing information containing predetermined informationrelated to the contents information stored in the data area, wherein anamount of the information containing the predetermined informationexceeds a value corresponding to an upper limit of an ability of thepredetermined error correction blocks to correct errors.

A third aspect of this invention is based on the first aspect thereof,and provides an information recording medium wherein the lead-ininformation contains flag information representing a validity of thelead-in information.

A fourth aspect of this invention is based on the first aspect thereof,and provides an information recording medium wherein the first lead-ininformation area and the second lead-in information area compriseinformation-recordable areas made of phase-changeable material, and thepredetermined information is reproducible.

A fifth aspect of this invention provides a method of recording lead-ininformation and contents information on an information recording medium,the information recording medium comprising a lead-in area and a dataarea for storing contents information, the lead-in area including afirst lead-in information area for storing the lead-in information and asecond lead-in information area for storing the lead-in informationexcept predetermined information related to the contents informationstored in the data area. The method comprises the steps of recording thelead-in information on the first lead-in information area, and recordingthe contents information on the data area during a first recording modeof operation which corresponds to recording on the first lead-ininformation area; and recording the lead-in information except thepredetermined information on the second lead-in information area, andrecording the contents information on the data area during a secondrecording mode of operation which corresponds to recording on the secondlead-in information area.

A sixth aspect of this invention provides an apparatus for recordinglead-in information and contents information on an information recordingmedium, the information recording medium comprising a lead-in area and adata area for storing contents information, the lead-in area including afirst lead-in information area for storing the lead-in information and asecond lead-in information area for storing the lead-in informationexcept predetermined information related to the contents informationstored in the data area. The apparatus comprises first means fordeciding which of a first recording mode of operation and a secondrecording mode of operation is selected, wherein the first recordingmode of operation corresponds to recording on the first lead-ininformation area, and the second recording mode of operation correspondsto recording on the second lead-in information area; second means forrecording the lead-in information on the first lead-in information area,and recording the contents information on the data area when the firstmeans decides that the first recording mode of operation is selected;and third means for recording the lead-in information except thepredetermined information on the second lead-in information area, andrecording the contents information on the data area when the first meansdecides that the second recording mode of operation is selected.

A seventh aspect of this invention provides a method of reproducingcontents information from an information recording medium, theinformation recording medium comprising a lead-in area and a data areafor storing the contents information, the lead-in area including a firstlead-in information area and a second lead-in information area. Themethod comprises the steps of reproducing lead-in information from thefirst lead-in information area during a first playback mode of operationwhich corresponds to the first lead-in information area; reproducinglead-in information from the second lead-in information area during asecond playback mode of operation which corresponds to the secondlead-in information area; and reproducing the contents information fromthe data area in cases where the lead-in information is reproduced fromone of the first lead-in information area and the second lead-ininformation area.

An eighth aspect of this invention provides an apparatus for reproducingcontents information from an information recording medium, theinformation recording medium comprising a lead-in area and a data areafor storing the contents information, the lead-in area including a firstlead-in information area and a second lead-in information area. Theapparatus comprises first means for scanning the first lead-ininformation area to reproduce lead-in information from the first lead-ininformation area during a first playback mode of operation whichcorresponds to the first lead-in information area; second means forscanning the second lead-in information area to reproduce lead-ininformation from the second lead-in information area during a secondplayback mode of operation which corresponds to the second lead-ininformation area; and third means for reproducing the contentsinformation from the data area in cases where one of the first means andthe second means reproduces the lead-in information from one of thefirst lead-in information area and the second lead-in information areaduring one of the first playback mode of operation and the secondplayback mode of operation.

A ninth aspect of this invention is based on the first aspect thereof,and provides an information recording medium wherein the first depth issmaller than λ/(8n), and the second depth is in a range of about λ/(4n)to about λ/(8n), where “λ” denotes a wavelength of reading laser lightand “n” denotes a refractive index of a material for the medium.

A tenth aspect of this invention is based on the second aspect thereof,and provides an information recording medium wherein an informationamount of the predetermined error correction blocks is equal to about 32Kbytes, and the upper limit of an ability of the predetermined errorcorrection blocks to correct errors corresponds to about 2 Kbytes, andwherein the amount of the information containing the predeterminedinformation is equal to about 8 Kbytes or more.

An eleventh aspect of this invention provides an information recordingmedium comprising a lead-in area and a data area for storing contentsinformation, the lead-in area including a first lead-in information areaand a second lead-in information area, the first lead-in informationarea having a first depth and being for storing first lead-ininformation related to the contents information stored in the data area,the first lead-in information including information of mediummanufacture and information of a contents-information start position,the second lead-in information area including pre-pits having a seconddepth greater than the first depth, the pre-pits representingpredetermined information related to the contents information stored inthe data area, the second lead-in information area including an area forstoring second lead-in information including the information of mediummanufacture and the information of the contents-information startposition.

A twelfth aspect of this invention provides an information recordingmedium comprising a lead-in area and a data area for storing contentsinformation, the lead-in area including a first lead-in information areaand a second lead-in information area, the first lead-in informationarea being for storing first lead-in information related to the contentsinformation stored in the data area in units of predetermined errorcorrection blocks, the first lead-in information including informationof medium manufacture and information of a contents-information startposition, the second lead-in information area being for inerasablystoring information containing predetermined information related to thecontents information stored in the data area, wherein an amount of theinformation containing the predetermined information exceeds a valuecorresponding to an upper limit of an ability of the predetermined errorcorrection blocks to correct errors, the second lead-in information areaincluding an area for storing second lead-in information including theinformation of medium manufacture and the information of thecontents-information start position.

A thirteenth aspect of this invention is based on the eleventh aspectthereof, and provides an information recording medium wherein each ofthe first lead-in information and the second lead-in informationcontains flag information representing a validity of the related lead-ininformation.

A fourteenth aspect of this invention is based on the eleventh aspectthereof, and provides an information recording medium wherein the firstlead-in information area and the second lead-in information areacomprise information-recordable areas made of phase-changeable material,and the predetermined information is reproducible but becomes unreadablewhen new information is recorded again.

A fifteenth aspect of this invention is based on the first aspectthereof, and provides an information recording medium wherein the firstlead-in information area corresponds to RTR standards, and the secondlead-in information area corresponds to DVD-Video standards.

A sixteenth aspect of this invention is based on the first aspectthereof, and provides an information recording medium wherein thepredetermined information comprises information of a CSS key having agiven value.

A seventeenth aspect of this invention provides a method of reproducingcontents information from an information recording medium, theinformation recording medium comprising a lead-in area and a data areafor storing the contents information, the lead-in area including a firstlead-in information area and a second lead-in information area. Themethod comprises the steps of reading out first lead-in information fromthe first lead-in information area; deciding whether or not the read-outfirst lead-in information is valid; reproducing the contents informationfrom the data area in response to the read-out first lead-in informationwhen it is decided that the read-out first lead-in information is valid;deciding whether or not second lead-in information is required to beread out from the second lead-in information area; and reading out thesecond lead-in information from the second lead-in information area, andreproducing the contents information from the data area in response tothe read-out first lead-in information and the read-out second lead-ininformation in cases where it is decided that the second lead-ininformation is required to be read out from the second lead-ininformation area.

An eighteenth aspect of this invention provides a method of reproducingcontents information from an information recording medium, theinformation recording medium comprising a lead-in area and a data areafor storing the contents information, the lead-in area including a firstlead-in information area and a second lead-in information area. Themethod comprises the steps of deciding whether first lead-in informationis present in or absent from the first lead-in information area; readingout the first lead-in information from the first lead-in informationarea when it is decided that the first lead-in information is present inthe first lead-in information area; deciding whether the read-out firstlead-in information is valid or invalid; reproducing the contentsinformation from the data area in response to the read-out first lead-ininformation when it is decided that the read-out first lead-ininformation is valid; and reading out second lead-in information fromthe second lead-in information area, and reproducing the contentsinformation from the data area in response to the read-out secondlead-in information in cases where it is decided that the first lead-ininformation is absent from the first lead-in information area or incases where it is decided that the read-out first lead-in information isinvalid.

A nineteenth aspect of this invention provides an apparatus forreproducing contents information from an information recording medium,the information recording medium comprising a lead-in area and a dataarea for storing the contents information, the lead-in area including afirst lead-in information area and a second lead-in information area.The apparatus comprises first means for reading out first lead-ininformation from the first lead-in information area; second means fordeciding whether or not the read-out first lead-in information is valid;third means for reproducing the contents information from the data areain response to the read-out first lead-in information when the secondmeans decides that the read-out first lead-in information is valid;fourth means for deciding whether or not second lead-in information isrequired to be read out from the second lead-in information area; andfifth means for reading out the second lead-in information from thesecond lead-in information area, and reproducing the contentsinformation from the data area in response to the read-out first lead-ininformation and the read-out second lead-in information in cases wherethe fourth means decides that the second lead-in information is requiredto be read out from the second lead-in information area.

A twentieth aspect of this invention provides an apparatus forreproducing contents information from an information recording medium,the information recording medium comprising a lead-in area and a dataarea for storing the contents information, the lead-in area including afirst lead-in information area and a second lead-in information area.The apparatus comprises first means for deciding whether first lead-ininformation is present in or absent from the first lead-in informationarea; second means for reading out the first lead-in information fromthe first lead-in information area when the first means decides that thefirst lead-in information is present in the first lead-in informationarea; third means for deciding whether the read-out first lead-ininformation is valid or invalid; fourth means for reproducing thecontents information from the data area in response to the read-outfirst lead-in information when the third means decides that the read-outfirst lead-in information is valid; and fifth means for reading outsecond lead-in information from the second lead-in information area, andreproducing the contents information from the data area in response tothe read-out second lead-in information in cases where the first meansdecides that the first lead-in information is absent from the firstlead-in information area or in cases where the third means decides thatthe read-out first lead-in information is invalid.

A twenty-first aspect of this invention is based on the seventeenthaspect of this invention, and provides a method wherein the informationrecording medium comprises an information recording medium of the firstaspect of this invention.

A twenty-second aspect of this invention is based on the nineteenthaspect thereof, and provides an apparatus wherein the informationrecording medium comprises an information recording medium of the firstaspect of this invention.

A twenty-third aspect of this invention provides a rewritableinformation-recording optical disc comprising a lead-in area assigned tolead-in information and a data area assigned to contents information,the lead-in area including a first sub-area and a second sub-area, thefirst sub-area corresponding to first disc standards and including aphase change recording area, the first sub-area being assigned tolead-in information corresponding to the first disc standards, thesecond sub-area corresponding to second disc standards different fromthe first disc standards and including pre-pits representative ofpredetermined information in a predetermined logic state, thepredetermined information relating to the contents information to whichthe data area is assigned, the second sub-area being assigned to lead-ininformation corresponding to the second disc standards, the data areaincluding a phase change recording area.

A twenty-fourth aspect of this invention is based on the first aspectthereof, and provides an information recording medium wherein thepredetermined information comprises information of copyright protectionrelated to the contents information stored in the data area.

A twenty-fifth aspect of this invention is based on the second aspectthereof, and provides an information recording medium wherein thepredetermined information comprises information of copyright protectionrelated to the contents information stored in the data area.

A twenty-sixth aspect of this invention is based on the fifth aspectthereof, and provides a method wherein the predetermined informationcomprises information of copyright protection related to the contentsinformation stored in the data area.

A twenty-seventh aspect of this invention is based on the sixth aspectthereof, and provides an apparatus wherein the predetermined informationcomprises information of copyright protection related to the contentsinformation stored in the data area.

A twenty-eighth aspect of this invention is based on the eleventh aspectthereof, and provides an information recording medium wherein thepredetermined information comprises information of copyright protectionrelated to the contents information stored in the data area.

A twenty-ninth aspect of this invention is based on the twelfth aspectthereof, and provides an information recording medium wherein thepredetermined information comprises information of copyright protectionrelated to the contents information stored in the data area.

A thirtieth aspect of this invention provides a rewritableinformation-recording optical disc comprising a lead-in area assigned tolead-in information and a data area assigned to contents information,the lead-in area including a first sub-area and a second sub-area, thefirst sub-area corresponding to first disc standards and including aphase change recording area, the first sub-area being assigned tolead-in information corresponding to the first disc standards, thesecond sub-area corresponding to second disc standards different fromthe first disc standards and including pre-pits representative ofcopyright protecting information in a predetermined logic state, thesecond sub-area being assigned to lead-in information corresponding tothe second disc standards, the data area including a phase changerecording area.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional diagram of an information recording mediumaccording to a first embodiment of this invention.

FIG. 2 is a diagram of the format of one data sector.

FIG. 3 is a diagram of the format of one ECC block.

FIG. 4 is a diagram of the format of data recorded on an informationrecording medium.

FIG. 5 is a diagram of the physical format of one sector.

FIG. 6 is a perspective view of a portion of the information recordingmedium in the first embodiment of this invention.

FIG. 7 is a sectional diagram of a laminate of layers from which amaster disc is formed.

FIG. 8 is a diagram of light quantity-sensitivity characteristics ofresist layers in FIG. 7.

FIG. 9 is a view including a diagram of variations in the intensity ofapplied light, and sectional diagrams of laminates and a stamper whichoccur during the fabrication of a master disc.

FIG. 10 is a block diagram of a recording and reproducing apparatusaccording to a second embodiment of this invention.

FIG. 11 is a flowchart of a portion of a program for a system controllerin FIG. 10.

FIG. 12 is a flowchart of a portion of a program for the systemcontroller in FIG. 10.

FIG. 13 is a flowchart of a portion of a program for the systemcontroller in FIG. 10.

FIG. 14 is a flowchart of a portion of a program for the systemcontroller in FIG. 10.

FIG. 15 is a diagram of the relation among one ECC block, a timingsignal, a pre-pit area, and a recorded signal.

FIG. 16 is a diagram of the relation among one ECC block, a timingsignal, and a pre-pit area.

DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment

An information recording medium (an information-recording optical disc)in a first embodiment of this invention is one of a DVD-RW (aDVD-Rewritable), a CD-RW (a CD-Rewritable), a DVD+RW (DVD+Rewritable), aDVD of another type, and another high-density large-capacity opticaldisc. In other words, the information recording medium of the firstembodiment of this invention conforms to the DVD-RW standards, the CD-RWstandards, the DVD+RW standards, the other DVD standards, or the otheroptical disc standards. The information recording medium (theinformation-recording optical disc) has a central hole which is of acircular shape.

As shown in FIG. 1, the information recording medium (theinformation-recording optical disc) has a lead-in area LI, a data areaDA, and a lead-out area LO. The lead-in area LI, the data area DA, andthe lead-out area are successively arranged in that order as viewedalong a radially outward direction of the disc. The lead-in area LIincludes a first area LI1 and a second area LI2 referred to as a firstlead-in area LI1 and a second lead-in area LI2 respectively. The secondlead-in area LI2 extends outward of the first lead-in area LI1.

Lead-in information contains information related to copyrightprotection. The copyright-protection-related information includes, forexample, a signal representing a CSS (contents scramble system) key. Thelead-in information is recorded or written on the lead-in area LI of theinformation recording medium. The lead-in information can be read outfrom the lead-in area LI. The writing of the lead-in information on thelead-in area LI of the information recording medium, and the read-out ofthe lead-in information therefrom are designed to satisfy the followingconditions {circle around (1)}, {circle around (2)}, and {circle around(3)}.

{circle around (1)} Lead-in information which contains a signal of a CSSkey is written on the first lead-in area LI1 of the informationrecording medium when main information (contents information) isrecorded on the data area DA thereof. Also, the lead-in information isrecorded on the second lead-in area LI2 of the information recordingmedium in advance. It should be noted that the CSS-key signal may beomitted from the lead-in information. In the case where the lead-ininformation contains the CSS-key signal, the lead-in information isrecorded on the first lead-in area LI1 in a manner such that it can berewritten or updated. On the other hand, copyright-protection-relatedinformation, such as information of a CSS key corresponding to a givenvalue or copy guard information, is recorded on the second lead-in areaLI2 in a manner such that it can be neither rewritten nor updated. Forexample, pre-pits representing the copyright-protection-relatedinformation are formed in the second lead-in area LI2 of the informationrecording medium.

{circle around (2)} A recorder-player for the information recordingmedium can operate in any one of different modes including a firstrecording mode, a second recording mode, a first playback mode, and asecond playback mode. During the first recording mode of operation, if asignal of a CSS key already exists in the first lead-in area LI1,lead-in information containing the signal of the CSS key is recorded onthe information recording medium (the first lead-in area LI). During thefirst playback mode of operation, if a signal of a CSS key alreadyexists in the first lead-in area LI1, lead-in information containing thesignal of the CSS key is reproduced from the information recordingmedium (the first lead-in area LI1). During the second recording mode ofoperation, if the second lead-in area LI2 has a recordable portion,lead-in information except copyright-protection-related information isrecorded on the second lead-in area LI2. During the second playback modeof operation, lead-in information containingcopyright-protection-related information is reproduced from the secondlead-in area LI2.

{circle around (3)} As previously mentioned,copyright-protection-related information, such as information of a CSSkey corresponding to a given value or copy guard information, isrecorded on the second lead-in area LI2 in a manner such that it can beneither rewritten nor updated. The copyright-protection-relatedinformation is represented by a train of pits, the total number of whichis equal to a predetermined value or greater so that thecopyright-protection-related information can not be altered by an errorcorrection process.

In the case where the previously-indicated conditions {circle around(1)}, {circle around (2)}, and {circle around (3)} are satisfied,copyright-protection-related information such as information of a CSSkey or copy guard information can be maintained by a compatible player.In addition, even if contents information inhibited by copyright frombeing copied is illegally recorded on the data area DA of an informationrecording medium, the contents information is prevented from beingreproduced therefrom. On the other hand, after free contents informationor contents information permitted by copyright to be copied is recordedon the data area DA of an information recording medium, the contentsinformation can be reproduced therefrom.

In more detail, the first embodiment of this invention has featuresindicated in the following items (1), (2), (3), and (4).

(1) A DVD-Video is designed for a playback purpose (a reproductionpurpose) only. In the DVD-Video, all of contents information and CSS-keyinformation recorded in an area of the disc which corresponds to thesecond lead-in area LI2 (see FIG. 1) are represented by pits in thedisc. The depth of these pits is equal to about λ/(4n) where “λ” denotesa reading laser light wavelength of about 650 nm, and “n” denotes arefractive index of a material (for example, polycarbonate) for thedisc. On the other hand, a DVD-RW is a rewritable disc on whichinformation is recorded by a phase change recording method. In theDVD-RW, recorded contents information is stored in a groove (a spiralgroove) in the disc. To optimize recording and reproducing performances,the depth of the groove relative to a land is set to about λ/(16n) orset in the range of λ/(10n) to λ/(18n). According to the firstembodiment of this invention, copyright-protection-related informationsuch as CSS-key information for a DVD-Video or copy guard information ispreviously recorded on a DVD-RW. Specifically, the DVD-RW is formed withpre-pits which represent the copyright-protection-related information,and which have a depth in the range of about λ/(4n) to about λ/(8n).Thus, the depth of the pre-pits in the DVD-RW is close to the depth ofthe information recording pits in the DVD-Video. Accordingly, aDVD-Video player is allowed to properly reproduce thecopyright-protection-related information from the DVD-RW. A disc area inwhich the pre-pits are located is referred to as a pre-pit area. Thepre-pit area extends in the second lead-in area LI2 (see FIG. 1).

(2) The DVD-Video player implements a block-by-block error correctionprocess on a signal read out from a recording disc, for example, aDVD-Video or a DVD-RW. It is now assumed that thecopyright-protection-related information recorded on the pre-pit area ofthe DVD-RW differs from rightful copyright-protection-relatedinformation for recorded contents information, and the data amount (thenumber of bits) of the recorded copyright-protection-related informationis within the range of the ability of an ECC (error correction code)block, containing the pre-pit area, to correct errors. In this assumedcase, although the player reads out the copyright-protection-relatedinformation from the pre-pit area of the DVD-RW, the player recovers therightful copyright-protection-related information as a result of theerror correction process on the read-out signal which corresponds to theECC block containing the pre-pit area. Thus, the player reproduces thecontents information in response to the rightfulcopyright-protection-related information (the rightful CSS-keyinformation or the rightful copy guard information). Accordingly, thedata amount of the copyright-protection-related information representedby the pre-pits in the DVD-RW is set to a value beyond the range of theability of an ECC block to correct errors. In the case where therightful copyright-protection-related information fails to be recovered,the player is inhibited from reproducing the contents information fromthe DVD-RW. Thus, it is possible to prevent the contents informationfrom being illegally copied.

(3) The copyright-protection-related information (the CSS-keyinformation or the copy guard information) same as that recorded on thepre-pit area is stored in a memory such as a ROM in a recorder-player.The copyright-protection-related information same as that recorded onthe pre-pit area may be fed to the recorder-player from an external. Inthe case where the second lead-in area LI2 (see FIG. 1) except thepre-pit area has a phase change recording region, data of an ECC-blockare generated from the copyright-protection-related information same asthat recorded on the pre-pit area and contents information to berecorded, and the ECC-block data are recorded on the second lead-in areaLI2 except the pre-pit area during a recording mode of operation of therecorder-player. Accordingly, during a later playback mode of operationof the recorder-player, the ECC block data can be reproduced as datacontaining the copyright-protection-related information.

(4) The features indicated in the previous items (1), (2), and (3)provide compatibility of the reproduction of contents information whichdoes not need copyright protection. In some cases, contents informationwhich does not need copyright protection is recorded on an RTR(real-time recording) disc incompatible with a DVD-Video regardingplayback. In view of this fact, lead-in information conforming to theRTR standards is recorded on the first lead-in area LI1 (see FIG. 1) ofthe information recording medium according to the first embodiment ofthis invention. This design enables the information recording medium tofulfill the requirements of the RTR standards in addition to the DVDstandards.

A signal recording format used in the first embodiment of this inventionwill be described hereinafter. In general, information to be recorded ona DVD-RW is of a physical structure containing a plurality of datasectors 20 each having 2064 bytes. As shown in FIG. 2, one data sector20 is composed of ID information 21, an ID-information error correctioncode (IED) 22, reserved data 23, a data region 24, and an errordetection code (EDC) 25 which are sequentially arranged in that orderalong a direction from the sector head toward the sector end. The IDinformation 21 indicates the start position of the data sector 20. TheID-information error correction code 22 is designed to correct an erroror errors in the ID information 21. For example, the reserved data 23are used for copyright management information (CPM). The data region 24stores main data to be recorded. The data region 24 has a sizecorresponding to 2048 bytes. The error detection code 25 is designed todetect an error or errors in the data region 24. A sequence of datasectors 20 compose information to be recorded.

The data sectors 20 are combined and changed into ECC blocks. Apredetermined number (16) of data sectors 20 are assigned to one ECCblock. As shown in FIG. 3, one data sector 20 is divided into 12equal-size segments each having 172 bytes. These segments are referredto as the data blocks 33. The 12 data blocks 33 are arranged in avertical direction.

For each of the data blocks 33, a 10-byte ECC inner code signal (a10-byte PI code signal or a 10-byte parity in code signal) 31 is addedto the block end. The addition of the 10-byte ECC inner code signalchanges the data block 33 into a correction block 34. Thus, 12correction blocks 34 are arranged in the vertical direction. A sequenceof the above-mentioned steps is reiterated a given number of times whichcorresponds to 16 data sectors 20. As a result, there are provided 192rows, that is, 192 correction blocks 34.

Subsequently, the arrangement of the 192 rows formed by the 192correction blocks 34 is divided into equal-size columns whose horizontaldimension corresponds to 1 byte. Then, 16 ECC outer code signals (POcode signals or parity out code signals) 32 are added to the bottom ofeach of the columns. It should be noted that ECC outer code signals areadded also to the bottoms of columns occupied by the ECC inner codesignals 31. The resultant arrangement of the rows and the columns formsone ECC block 30. As understood from the previous description, 16 datasectors 20 are contained in one ECC block 30.

The total amount (the total number of bits) of information in one ECCblock 30 is equal to 37856 bytes as expressed by the following equation.

37856 bytes=(172+10)bytes multiplied by(192+16)rows

The total amount (the total number of bits) of data stored in the dataregions 24 assigned to one ECC block 30 is equal to 32768 bytes asexpressed by the following equation.

32768 bytes=2048 bytes multiplied by 16

In the ECC block 30 of FIG. 3, a 1-byte data piece is denoted by “D#.*”. For example, “D1. 0” denotes the 1-byte data piece in the 1-st rowand the 0-th column, and “D190. 170” denotes the 1-byte data piece inthe 190-th row and the 170-th column. Thus, the ECC inner code signals31 are placed in the range of the 172-nd column to the 181-st column. Onthe other hand, the ECC outer code signals 32 are placed in the range ofthe 192-nd row to the 207-th row.

One correction block 34 is continuously recorded on the DVD-RW.Regarding the ECC block 30 of FIG. 3, correction of errors in thehorizontally-extending data sequences is executed in response to the ECCinner code signals 31. On the other hand, correction of errors in thevertically-extending data sequences is executed in response to the ECCouter code signals 32. Thus, the data in the ECC block 30 can besubjected to a double error correction process having an errorcorrection process along the horizontal direction and an errorcorrection process along the vertical direction. Therefore, it ispossible to provide a higher ability to correct errors than that of anerror correction process used in a prior-art CD.

As previously mentioned, one correction block 34 which is continuouslyrecorded on the DVD-RW has 182-byte data including a 10-byte ECC innercode signal 31 corresponding to one row. In one correction block 34, itis possible to correct errors of 5 bytes or less in response to the ECCinner code signal 31. In one correction block 34, it is difficult tocorrect errors of 6 bytes or more in response to the ECC inner codesignal 31. Such many-byte errors in the horizontal direction correspondto an error of 1 byte as viewed in the vertical direction or the columndirection. Therefore, it is possible to correct the many-byte errors inresponse to ECC outer code signals 32 even when the many-byte errorsfully occupy one correction block 34. The maximum vertical dimension ofan error group which can be corrected correspond to 8 rows (16 rows inthe case of erasure-based correction).

With reference to the portion (A) of FIG. 4, correction blocks 34composing one ECC block 30 are sequentially arranged along a horizontaldirection. Data pieces “D#. *” in FIG. 4 correspond to those in FIG. 3.The sequence of correction blocks 34 is interleaved, being divided into16 recording sectors 40 (see the portion (B) of FIG. 4). Each recordingsector 40 has a size corresponding to 2366 bytes (37856 bytes divided by16). A data sector 20, ECC inner code signals 31, and ECC outer codesignals 32 exist in one recording sector 40 on a mixed basis. The headof each recording sector 40 is loaded with ID information 21 (see FIG.2) in a data sector 20.

As shown in the portions (B) and (C) of FIG. 4, each recording sector 40is divided into 91-byte data segments 41. Sync signals H are added tothe heads of data segments 41, respectively. Then, each sync-addedrecording sector 40 is subjected to 8-16 modulation so that sync frames42 are generated from data segments 41 respectively. As shown in theportion (D) of FIG. 4, each sync frame 42 is composed of a sync signalH′ and a data segment 43. Each sync frame 42 has a size corresponding to1456 bytes (equal to 91 bytes multiplied by

$\left. {8 \cdot \frac{16}{8}} \right).$

A sequence of sync frames 42 is written on a DVD-RW. In this case, onerecording sector 40 corresponds to 26 sync frames 42.

Each ECC block 30 is composed of 16 physical sectors. FIG. 5 shows afirst physical sector in an ECC sector 30. The physical sector in FIG. 5has 13 horizontal rows. Each of the first to twelfth horizontal rows has186 bytes equal to the sum of 172 bytes of data, 10 bytes of a PI codesignal, and 4 bytes of sync signals. The thirteenth horizontal row has186 bytes of PO code signals. The physical sector in FIG. 5 has 26 syncsignals H0-H25 each having 2 bytes. Two sync signals are assigned to onehorizontal row.

The previously-mentioned physical format is formed, and informationcontaining ECC blocks 30 is recorded on a DVD-RW. During the playback ofan after-recording DVD-RW, a signal is read out from the disc and theread-out signal is subjected to 8-16 demodulation and deinterleave sothat the original ECC blocks 30 are reproduced. In this case, it ispossible to minimize a damaged data block size. Furthermore, thepreviously-mentioned double error correction process enables theoriginal information to be accurately reproduced. Copy guard information(copyright-protection-related information or CSS-key information) isrecorded on the second lead-in area LI2 (see FIG. 1) of the disc as datain a portion of an ECC block 30.

With reference to FIGS. 1 and 6, an information recording medium (aninformation-recording optical disc) “D” in the first embodiment of thisinvention has a lead-in area LI and a data area DA. The data area DAextends outward of the lead-in area LI. The lead-in area LI includes afirst area LI1 and a second area LI2 referred to as a first lead-in areaLI1 and a second lead-in area LI2 respectively. The second lead-in areaLI2 extends outward of the first lead-in area LI1. The first lead-inarea LI1 corresponds to a first recording and playback mode of apparatusoperation (for example, an RTR playback mode of operation, that is,playback by an RTR player). The second lead-in area LI2 corresponds to asecond recording and playback mode of apparatus operation (for example,a DVD compatible playback mode of operation, that is, playback by aDVD-Video player). Contents information such as audio contentsinformation or audio visual contents information is recorded on the dataarea DA.

The first lead-in area LI1 is formed with a groove (a spiral groove) “G”which has a first predetermined depth d1 (see FIG. 6) relative to a land“L”, and which stores, on a phase change recording basis, lead-ininformation corresponding to the contents information recorded on thedata area DA. The lead-in information on the first lead-in area LI1contains, for example, information of the manufacture of the disc andinformation of a contents start position. In FIG. 6, the referencecharacter “Le” denotes the direction of an information-recording laserbeam or an information-reading laser beam applied to the informationrecording medium “D”. The second lead-in area LI2 includes a pre-pitarea PR formed with pre-pits “pr” which have a second predetermineddepth d2 (see FIG. 6) relative to the land “L”, and which representcopyright-protection-related information and also lead-in information.The second predetermined depth d2 is greater than the firstpredetermined depth d1. The lead-in information on the second lead-inarea LI2 corresponds to the contents information recorded on the dataarea DA, and contains, for example, information of the manufacture ofthe disc and information of the contents start position. Thecopyright-protection-related information on the second lead-in area LI2concerns the contents information recorded on the data area DA.

The lead-in information on the first lead-in area LI1 corresponds to thecontents information which is recorded on the data area DA on anECC-block-by-ECC-block basis. As previously mentioned, the lead-ininformation on the first lead-in area LI1 contains, for example,information of the manufacture of the disc and information of a contentsstart position.

The recording of the copyright-protection-related information on thesecond lead-in area LI2 is designed to prevent thecopyright-protection-related information from being erased or alteredduring a later overwrite process. In the case where the upper limit ofthe ability of one ECC block to correct errors corresponds to aninformation amount of “n” bytes, the amount of thecopyright-protection-related information on the second lead-in area LI2is set greater than “n” bytes. In other words, the amount of thecopyright-protection-related information on the second lead-in area LI2is set beyond the upper limit of the ability of one ECC block to correcterrors.

The information recording medium (the information-recording opticaldisc) “D” in the first embodiment of this invention features that thelead-in information on the first lead-in area LI1 or the second lead-inarea LI2 contains flag information indicating the validity of thelead-in information. The flag information has category-indicatinginformation such as standards-related information and versioninformation (media-type information).

In addition, the information recording medium (the information-recordingoptical disc) “D” in the first embodiment of this invention has thefollowing features. Information is recorded on the medium by a phasechange recording method. The copyright-protection-related informationcan be read out from the second lead-in area LI2.

The information-recording optical disc (the information recordingmedium) “D” in the first embodiment of this invention is fabricated asfollows. With reference to FIG. 7, a second resist layer 1B, anintermediate layer 1C, and a first resist layer 1D are sequentiallyformed on a glass substrate 1A as a laminate. The sum of the thicknessof the intermediate layer 1C and the thickness of the first resist layer1D is set equal to the depth d1 of the groove “G” in phase changerecording areas “R” of the recording medium “D” (see FIG. 6). The sum ofthe thickness of the second resist layer 1B, the thickness of theintermediate layer 1C, and the thickness of the first resist layer 1D isset equal to the depth d2 of pre-pits “pr” in the pre-pit area PR of therecording medium “D” (see FIG. 6).

A light exposure process (a laser recording process) is performed on thelaminate. Specifically, laser light having a first predeterminedintensity is applied to the first resist layer 1D from above. The firstpredetermined intensity is chosen so that the first resist layer 1D andthe intermediate layer 1C undergo light exposure and hence the shapes ofrecording areas “R” are formed on the glass substrate 1A. In addition,laser light having a second predetermined intensity is applied to thefirst resist layer 1D from above. The second predetermined intensity isset greater than the first predetermined intensity so that the firstresist layer 1D, the intermediate layer 1C, and the second resist layer1B undergo light exposure and hence a pre-pit area PR is formed on theglass substrate 1A.

In more detail, the first resist layer 1D and the second resist layer 1Bare made of commercially available material such as “THMLIP3100”produced by Tokyo Ohka Kogyo Co., Ltd. The intermediate layer 1C extendsbetween the first resist layer 1D and the second resist layer 1B, andseparates them from each other. The intermediate layer 1C is a film ofphotosensitive material such as polyvinyl alcohol which is formed byspin coat. As previously mentioned, the second resist layer 1B, theintermediate layer 1C, and the first resist layer 1D are sequentiallyformed on the glass substrate 1A as a laminate. According to lightquantity-sensitivity characteristics 1DD in FIG. 8, the first resistlayer 1D is designed to react to a low light quantity (a low lightintensity) of recording krypton laser light having a wavelength of 351nm. According to light quantity-sensitivity characteristics 1BB in FIG.8, the second resist layer 1B is designed to react to a high lightquantity (a high light intensity) of the recording krypton laser light.As shown in FIG. 9, during the laser recording process, the intensity ofthe recording krypton laser light is changed among a predetermined highlevel, a predetermined normal level (a predetermined intermediatelevel), and a predetermined low level to form a groove (or grooves) “G”,pre-pits “pr”, and a land “L”. The pre-pits “pr”, and land portions “L”therebetween compose a pre-pit area PR. During the light exposure toform the pre-pit area PR, the change of the intensity of the recordingkrypton laser light is controlled in response tocopyright-protection-related information. Thus, thecopyright-protection-related information is recorded on the pre-pit areaPR. The length of the pre-pit area PR is set to a predetermined value.

The resultant laminate is subjected to development. After thedevelopment, the layers on the glass substrate 1A have shapes such asshown in the portion (C) of FIG. 9. Subsequently, an electricallyconductive film such as a nickel film is formed on exposed upper andside surfaces of the first resist layer 1D, the intermediate layer 1C,the second resist layer 1B, and the glass substrate 1A by electrolessplating. A film having a thickness of, for example, about 250 μm isdeposited on the electrically conductive film by electroplating to forma stamper (see the portion (D) of FIG. 9).

The stamper is attached to a die. Resin such as polycarbonate is shapedinto a disc base by an injection molding process using the die with thestamper. A phase change recording film is formed on the disc base by asputtering process. A protective film is formed on the phase changerecording film. The disc base with the recording film and the protectivefilm is initialized so that a virgin information-recording optical discis completed. The virgin information-recording optical disc has areasincluding a first lead-in area LI1, a second lead-in area LI2, and adata area DA (see FIG. 1). The data area DA and the first lead-in areaLI1 has grooves (spiral grooves) “G” whose depth is equal to aboutλ/(16n). The data area DA and the first lead-in area LI1 are phasechange recording areas or information recordable areas. On the otherhand, the second lead-in area LI2 contains a pre-pit area PR havingpre-pits “pr” whose depth is in the range of about λ/(4n) to aboutλ/(8n). The pre-pits “pr” represent the copyright-protection-relatedinformation on an unalterable basis or an inerasable basis.

In the information-recording optical disc, the length of the pre-pitarea PR is equal to a predetermined value corresponding to more than theupper limit of the ability of an ECC block to correct errors, that is,corresponding to more than 16 rows (or 8 rows) in an ECC block. Aspreviously mentioned, one sector has 13 rows (see FIG. 5). Thus, thelength of the pre-pit area PR is equal to a predetermined valuecorresponding to two sectors or more. Preferably, the length of thepre-pit area PR is equal to a value corresponding to four sectors.Accordingly, in the case where the copyright-protection-relatedinformation has not been successfully read out from the pre-pit area PRduring playback, the copyright-protection-related information can not berecovered by the error correction process on an ECC block containing thepre-pit area PR. The absence of the recoveredcopyright-protection-related information prevents related contentsinformation from being illegally copied since the reproduction of thecontents information requires the recovered copyright-protection-relatedinformation.

The copyright-protection-related information is, for example,information of a CSS key corresponding to a given value (that is, a CSSkey in a given logic state). An example of the CSS-key information is inan all-0 state. Preferably, the CSS-key information is in one of givenlogic states never assigned to normal contents information. It isassumed that the information-recording optical disc stores given CSS-keyinformation in its pre-pit area PR, and contents information scrambledaccording to a CSS is illegally recorded on the data area DA of theoptical disc. Usually, CSS-key information corresponding to theillegally-recorded contents information is different from the givenCSS-key information so that the contents information can not bedescrambled during playback. On the other hand, after unscrambledcontents information is recorded on the data area DA of theinformation-recording optical disc, the contents information can bereproduced from the optical disc.

It is assumed that contents information and corresponding CSS-keyinformation are illegally copied and overwritten onto the data area DAand the pre-pit area PR of the information-recording optical discrespectively by a phase change recording method. The pre-pits “pr” inthe pre-pit area PR cause errors in the phase-change-recorded CSS-keyinformation (the illegally-copied CSS-key information) on the pre-pitarea PR during playback. Thus, for the illegally-copied contentsinformation on the optical disc, the pre-pit area PR stores errorsinstead of the correct CSS-key information. Since the length of thepre-pit area PR corresponds to more than the upper limit of the abilityof an ECC block to correct errors, the accurate CSS-key information forthe illegally-copied contents information can not be recovered by theerror correction process. Therefore, it is difficult to reproduce theillegally-copied contents information from the optical disc.

The CSS-key information on the pre-pit area PR of theinformation-recording optical disc is data resulting from modulationaccording to the DVD-Video standards. The CSS-key data have asynchronized phase relation with an LPP address. Preferably, the depthof pre-pits “pr” in the pre-pit area PR is chosen to optimize an RFreproduced signal and a servo signal (for example, a tracking errorsignal) during playback by a DVD-Video apparatus. Preferably, the depthof pre-pits “pr” in the pre-pit area PR is chosen to optimize a servosignal (for example, a tracking error signal) during recording.

Second Embodiment

A second embodiment of this invention is directed to an apparatus forrecording and reproducing lead-in information and contents informationon and from an optical disc of the physical format in the firstembodiment of this invention. The apparatus is also referred to as therecording and reproducing apparatus.

With reference back to FIG. 1, the optical disc has a lead-in area LIand a data area DA. The lead-in area LI extends inward of the data areaDA. The lead-in area LI includes a first area LI1 and a second area LI2assigned to lead-in information containing information of themanufacture of the disc, information of a contents start position, andcopyright-protection-related information (CSS-key information or copyguard information). The first area LI1 and the second area LI2 arereferred to as the first lead-in area LI1 and the second lead-in areaLI2 respectively. The second lead-in area LI2 extends outward of thefirst lead-in area LI1. For example, each of the first lead-in area LI1and the second lead-in area LI2 is composed of 192 ECC blocks. Thelead-in information also contains flag information indicating thevalidity of the lead-in information. The first lead-in area LI1 forms arecording area “R” having a phase change recording layer. The secondlead-in area LI2 includes a pre-pit area PR storingcopyright-protection-related information (CSS-key information or copyguard information). The second lead-in area LI2 except the pre-pit areaPR forms a recording area (or recording areas) “R” having a phase changerecording layer. Data of “0” are recorded on the lead-in area LI exceptthe first lead-in area LI1 and the second lead-in area LI2.

Preferably, the optical disc is a DVD-RW. The DVD-RW has a spiralrecording track. The DVD-RW has address pre-pits (land-pre-pits) inaddition to pre-pits “pr” in the pre-pit area PR. The address pre-pitsare formed in a land extending along the recording track. The addresspre-pits represent information of sector addresses on the disc. At aninitial stage of a recording mode of operation of the apparatus, theaddress information is reproduced from the address pre-pits in theDVD-RW. During a later stage of the recording mode of operation,recording positions on the DVD-RW are decided in response to the addressinformation, and lead-in information and contents information arerecorded on the decided recording positions of the DVD-RW.

With reference to FIG. 10, the recording and reproducing apparatusincludes a spindle motor 2, an optical head 3, an amplifier unit 4, asignal processor 5, an audio-video encoding and decoding unit 6, adriver 7, a servo unit 8, a system controller 9, a key input unit 10, aninput/output terminal 11, an input terminal 12, an interface 13, a trackbuffer memory 14, and a memory 15.

The spindle motor 2 rotates an optical disc 1. The optical head 3 writesand reads information on and from the optical disc 1. The spindle motor2 is connected to the driver 7. The optical head 3 is connected to theamplifier unit 4 and the driver 7. The amplifier unit 4 is connected tothe signal processor 5 and the servo unit 8. The driver 7 is connectedto the servo unit 8. The signal processor 5 is connected to theaudio-video encoding and decoding unit 6 and the track buffer memory 14.The audio-video encoding and decoding unit 6 is connected to the memory15 and the input/output terminal 11. The system controller 9 isconnected to the amplifier unit 4, the signal processor 5, theaudio-video encoding and decoding unit 6, the servo unit 8, the keyinput unit 10, the input terminal 12, and the interface 13.

The optical disc 1 is of a rewritable type. The optical disc 1 is madeof phase changeable material. The optical disc 1 is, for example, aDVD-RW. The DVD-RW has a spiral track being a sequence of sectors whichextends along a spiral. During the recording of information or thereproduction of information, the DVD-RW is rotated at a constant linearvelocity (CLV). In the DVD-RW, 16 successive sectors compose one ECCblock. The optical disc 1 is coupled with the spindle motor 2 by achucking mechanism (not shown).

The spindle motor 2 is driven and controlled by the driver 7. Thespindle motor 2 rotates the optical disc 1 chucked thereto. The spindlemotor 2 is provided with an FG generator and a rotational positionsensor (an angular position sensor). The rotational position sensorincludes, for example, a Hall element. The FG generator outputs an FGsignal to the driver 7. The Hall element outputs a rotational positionsignal to the driver 7. The FG signal and the rotational position signalare fed back to the servo unit 8 via the driver 7 as rotation servosignals.

The optical head 3 includes a semiconductor laser, a collimator lens,and an objective lens. The semiconductor laser acts as a source foremitting a light beam (a laser beam) Le. The emitted laser beam Le isfocused into a laser spot on a track of the optical disc 1 by thecollimator lens and the objective lens. The optical head 3 includes a2-axis actuator for driving the objective lens to implement focusing andtracking of the laser spot with respect to the optical disc 1. Thesemiconductor laser is driven by a drive circuit in the optical head 3or the driver 7. The 2-axis actuator is driven by the driver 7.

The key input unit 10 includes a plurality of keys which can be operatedby a user. The key input unit 10 generates command signals in accordancewith its operation by the user. The command signals are transmitted fromthe key input unit 10 to the system controller 9. The command signalsinclude a command signal for starting a recording mode of operation ofthe apparatus, a command signal for starting a playback mode ofoperation of the apparatus, a command signal for stopping the recordingmode of operation of the apparatus, and a command signal for stoppingthe playback mode of operation of the apparatus. The key input unit 10generates control data in accordance with its operation by the user. Thecontrol data are transmitted from the key input unit 10 to the systemcontroller 9.

The interface 13 is designed for data communications with an externalapparatus such as a computer. The interface 13 is of an ATAPI (advancedtechnology attachment packet interface) type.

The system controller 9 includes, for example, a microcomputer or asimilar device which operates in accordance with a program stored in itsinternal ROM. The system controller 9 controls the amplifier unit 4, thesignal processor 5, the audio-video encoding and decoding unit 6, andthe servo unit 8 in response to the command signals fed from the keyinput unit 10. The system controller 9 implements data communicationswith an external apparatus via the interface 13.

Control data can be fed to the system controller 9 via the inputterminal 12. The control data fed to the system controller 9 via theinput terminal 12, and the control data fed to the system controller 9from the key input unit 10 include a signal for adjusting the resolutionof pictures represented by contents information to be recorded, a signalfor separating quickly-moving scenes such as car racing scenesrepresented by contents information, and a signal for giving priority toa recording time. The system controller 9 changes an actual recordingtime in accordance with the control data. The system controller 9enables the setting of the actual recording time to be selected by theuser.

When the apparatus is required to start to operate in the playback mode,the key input unit 10 is actuated to generate the playback start commandsignal. The playback start command signal is transmitted from the keyinput unit 10 to the system controller 9. The system controller 9controls the amplifier unit 4 and the servo unit 8 in response to theplayback start command signal, thereby starting the playback mode ofoperation of the apparatus. The control of the servo unit 8 includessteps of controlling the driver 7. Firstly, the system controller 9starts rotation of the optical disc 1 and application of a laser spotthereon through the control of the driver 7. The optical head 3 iscontrolled by the driver 7, thereby reading out address information fromland pre-pits (address pre-pits) in a track on the optical disc 1. Theread-out address information is transmitted from the optical head 3 tothe system controller 9 via the amplifier unit 4. The system controller9 finds or decides a target sector (a target track portion) to be playedback by referring to the address information. The system controller 9controls the optical head 3 via the servo unit 8 and the driver 7,thereby moving the laser spot to the target sector on the optical disc1. When the movement of the laser spot to the target sector iscompleted, the system controller 9 operates to start the reproduction ofa signal from the target sector on the optical disc 1. In this way, theplayback mode of operation of the apparatus is started. During theplayback mode of operation of the apparatus, the target sector ischanged from one to another.

During the playback mode of operation of the apparatus, the optical head3 scans the optical disc 1 and generates an RF signal containinginformation read out therefrom. The optical head 3 outputs the RF signalto the amplifier unit 4. The amplifier unit 4 enlarges the RF signal. Inaddition, the amplifier unit 4 generates a main reproduced signal, andtracking and focusing servo signals (tracking error and focusing errorsignals) from the enlarged RF signal. The amplifier unit 4 includes anequalizer for optimizing the frequency aspect of the main reproducedsignal. Also, the amplifier unit 4 includes a PLL (phase locked loop)circuit for extracting a bit clock signal from the equalized mainreproduced signal, and for generating a speed servo signal from theequalized main reproduced signal. Furthermore, the amplifier unit 4includes a jitter generator for comparing the time bases of the bitclock signal and the equalized main reproduced signal, and for detectingjitter components from the results of the time-base comparison. A signalof the detected jitter components is transmitted from the amplifier unit4 to the system controller 9. The tracking and focusing servo signalsand the speed servo signal are transmitted from the amplifier unit 4 tothe servo unit 8. The equalized main reproduced signal is transmittedfrom the amplifier unit 4 to the signal processor 5.

The servo unit 8 receives the speed servo signal and the tracking andfocusing servo signals from the amplifier unit 4. The servo unit 8receives the rotation servo signals from the spindle motor 2 via thedriver 7. In response to these servo signals, the servo unit 8implements corresponding servo control processes.

Specifically, the servo unit 8 generates a rotation control signal onthe basis of the speed servo signal and the rotation servo signals. Therotation control signal is transmitted from the servo unit 8 to thespindle motor 2 via the driver 7. The spindle motor 2 rotates at a speeddepending on the rotation control signal. The rotation control signal isdesigned to rotate the optical disc 1 at a given constant linearvelocity. The recording and reproduction of information on and from theoptical disc 1 are implemented at a desired data transmission ratehigher than a maximum data transmission rate which occurs in datacompression and expansion executed in the apparatus. Accordingly, therotation control signal is designed so that the given constant linearvelocity will allow the attainment of the desired data transmission ratein the recording and reproduction of information on and from the opticaldisc 1.

In addition, the servo unit 8 generates servo control signals on thebasis of the focusing and tracking servo signals. The servo controlsignals are transmitted from the servo unit 8 to the 2-axis actuator inthe optical head 3 via the driver 7. The 2-axis actuator controls thelaser spot on the optical disc 1 in response to the servo controlsignals, and thereby implements focusing and tracking of the laser spotwith respect to the optical disc 1.

During the playback mode of operation of the apparatus, the signalprocessor 5 receives the main reproduced signal from the amplifier unit4. The signal processor 5 converts the main reproduced signal into acorresponding reproduced digital signal. The signal processor 5 detectsa sync signal from the reproduced digital signal. The signal processor 5decodes an EFM+ signal (an 8-16 modulation signal) of the reproduceddigital signal into NRZ data, that is, non-return-to-zero data. Thesignal processor 5 subjects the NRZ data to an error correction process,thereby generating address data and reproduced data. The address datarepresent the address of a currently-accessed sector on the optical disc1. The sync signal and the address data are fed from the signalprocessor 5 to the system controller 9.

In the case where the reproduced data are MPEG data resulting fromcompression at a variable transmission rate, the signal processor 5temporarily stores the reproduced data in the track buffer memory 14. Inaddition, writing and reading the data into and from the track buffermemory 14 are controlled to absorb a time-domain change in thetransmission rate of the reproduced data. The track buffer memory 14includes, for example, a D-RAM having a capacity of 64 Mbytes. The trackbuffer memory 14 means a buffer memory in which compressed data aretemporarily stored. The track buffer memory 14 contains a buffer memoryfor absorbing a time-domain change in the transmission rate of DVD data,and a buffer memory used in encoding and decoding MPEG data. Forexample, the system controller 9 implements the control of the datawrite and data read-out into and from the track buffer memory 14 via thesignal processor 5. In addition, the system controller 9 implementsmanagement of a used storage area and a used storage size in the trackbuffer memory 14 via the signal processor 5. The signal processor 5receives the read-out data (the reproduced data) from the track buffermemory 14. The signal processor 5 outputs the reproduced data to theaudio-video encoding and decoding unit 6.

In the case where the reproduced data fed from the track buffer memory14 via the signal processor 5 are compressed MPEG2 data in which audiodata and video data are multiplexed, the audio-video encoding anddecoding unit 6 separates the reproduced data into compressed audio dataand compressed video data. The audio-video encoding and decoding unit 6expands and decodes the compressed audio data into non-compressed audiodata. In addition, the audio-vide encoding and decoding unit 6 expandsand decodes the compressed video data into non-compressed video data.During the expansively decoding process, the audio-video encoding anddecoding unit 6 temporarily stores data in the memory 15. The memory 15includes, for example, a D-RAM having a capacity of 64 Mbytes. Theaudio-video encoding and decoding unit 6 converts the non-compressedaudio data into a corresponding analog audio signal throughdigital-to-analog conversion. Also, the audio-video encoding anddecoding unit 6 converts the non-compressed video data into acorresponding analog video signal through digital-to-analog conversion.It should be noted that the conversion of the non-compressed audio andvideo data into the analog audio and video signals may be implemented bydigital-to-analog converters provided externally of the audio-videoencoding and decoding unit 6. The audio-video encoding and decoding unit6 applies the analog audio signal and the analog video signal to theinput/output terminal 11. The analog audio signal and the analog videosignal are transmitted to an external via the input/output terminal 11.The analog video signal transmitted from the input/output terminal 11 isprocessed by an NTSC encoder before the processing-resultant videosignal is indicated on a monitor device (a display). The analog audiosignal transmitted from the input/output terminal 11 is fed to aloudspeaker, being converted thereby into a corresponding sound.

The data rate of the expansively decoding process by the audio-videoencoding and decoding unit 6, that is, the data transmission rate in theexpansively decoding process, is equalized to an expansion data ratewhich is set in accordance with the type of the related recording modeof operation of the apparatus. Specifically, the audio-video encodingand decoding unit 6 can implement the expansively decoding process at aexpansion data rate which can be changed among plural differentexpansion data rates. The audio-video encoding and decoding unit 6selects one from among the plural different expansion data rates as adesired expansion data rate in accordance with the type of the relatedrecording mode of operation of the apparatus. The audio-video encodingand decoding unit 6 executes the expansively encoding process at thedesired expansion data rate. Information of the type of the recordingmode of operation of the apparatus is recorded on the optical disc 1 ascontrol data. During the playback of the optical disc 1, the controldata are read out therefrom before being transmitted to the systemcontroller 9. The system controller 9 sets the expansion data rate inthe audio-video encoding and decoding unit 6 in accordance with thecontrol data.

When the apparatus is required to start to operate in the recordingmode, the key input unit 10 is actuated to generate the recording startcommand signal. The recording start command signal is transmitted fromthe key input unit 10 to the system controller 9. The system controller9 controls the amplifier unit 4 and the servo unit 8 in response to therecording start command signal, thereby starting the recording mode ofoperation of the apparatus. The control of the servo unit 8 includessteps of controlling the driver 7. Firstly, the system controller 9starts rotation of the optical disc 1 and application of a laser spotthereon through the control of the driver 7. The optical head 3 iscontrolled by the driver 7, thereby reading out address information fromland pre-pits (address pre-pits) in a track on the optical disc 1. Theread-out address information is transmitted from the optical head 3 tothe system controller 9 via the amplifier unit 4. The system controller9 finds or decides a target sector (a target track portion), on which asignal is to be recorded, by referring to the address information. Thesystem controller 9 controls the optical head 3 via the servo unit 8 andthe driver 7, thereby moving the laser spot to the target sector on theoptical disc 1. During the recording mode of operation of the apparatus,the target sector is changed from one to another.

During the recording mode of operation of the apparatus, an audio signaland a video signal to be recorded are fed via the input/output terminal11 to the audio-video encoding and decoding unit 6. The audio-videoencoding and decoding unit 6 converts the audio signal intocorresponding audio data through analog-to-digital conversion. Inaddition, the audio-video encoding and decoding unit 6 converts thevideo signal into corresponding video data through analog-to-digitalconversion. It should be noted that the conversion of the audio andvideo signals into the audio and video data may be implemented byanalog-to-digital converters provided externally of the audio-videoencoding and decoding unit 6. The audio-video encoding and decoding unit6 compressively encodes the audio data and the video data into MPEG2audio data and MPEG2 video data at a rate depending on the type of therecording mode. The audio-video encoding and decoding unit 6 multiplexesthe MPEG2 audio data and the MPEG2 video data to form multiplexed MPEG2data. The audio-vide encoding and decoding unit 6 outputs themultiplexed MPEG2 data to the signal processor 5. The data rate of thecompressively encoding process by the audio-video encoding and decodingunit 6, that is, the data transmission rate in the compressivelyencoding process, is equalized to a compression data rate which isselected from among plural different rates in accordance with the typeof the recording mode of operation of the apparatus. During thecompressively encoding process, the audio-video encoding and decodingunit 6 temporarily stores data in the memory 15.

It should be noted that the multiplexed MPEG2 data may be replaced bystill-picture data or computer data such as program file data. In thiscase, the still-picture data or the computer data are transmitted to thesystem controller 9 via the interface 13. The system controller 9transfers the still-picture data or the computer data to the signalprocessor 5.

During the recording mode of operation of the apparatus, the signalprocessor 5 adds error correction code signals (ECC signals or PI and POsignals) to the multiplexed MPEG2 data, the still-picture data, or thecomputer data. The signal processor 5 subjects the ECC-added data to NRZand EFM+ encoding processes. The signal processor 5 adds a sync signalto the encoding-resultant data to form sync-added data. The sync signalis fed from the system controller 9. The sync-added data are temporarilystored in the track buffer memory 14. The sync-added data are read outfrom the track buffer memory 14 at a data rate corresponding to a datarate of signal recording on the optical disc 1. The signal processor 5subjects the read-out data to given modulation for record. The signalprocessor 5 outputs the modulation-resultant signal to the amplifierunit 4. The amplifier unit 4 corrects the waveform of the output signalof the signal processor 5. The amplifier unit 4 outputs thewaveform-correction-resultant signal to the laser drive circuit in theoptical head 3. The optical head 3 records the output signal of theamplifier unit 4 on the target sector (the target track portion) on theoptical disc 1.

The amplifier unit 4 informs the system controller 9 of detected jittercomponents. The system controller 9 subjects the detected jittercomponents to analog-to-digital conversion to generate a measured jittervalue. During the recording mode of operation of the apparatus, thesystem controller 9 adjusts the degree or characteristic of the waveformcorrection by the amplifier unit 4 in response to the measured jittervalue and an asymmetry value.

The optical disc 1 will be further described. Preferably, the opticaldisc 1 is based on a DVD-RW. In other words, the optical disc 1 is amodification of a DVD-RW. The optical disc 1 conforms to the standardsof a recordable DVD. Regarding recorded contents, the optical disc 1 iscompatible with a DVD-Video, a DVD-Audio, a DVD-ROM, a DVD of anothertype, or another high-density large-capacity optical disc. Addresses ofsectors are previously recorded or formed on the DVD-RW. The recordedsector addresses enable address control to be implemented during therecording mode and the playback mode of operation of the apparatus. Theoptical disc 1 has a spiral groove corresponding to a spiral track. Forexample, the spiral groove is wobbled at a frequency modulated on thebasis of data representing addresses, and hence the addresses arerecorded on the optical disc 1 as a groove wobbling frequency signal.Preferably, the optical disc 1 has given pits (address pre-pits) whichare previously formed in a land. The given pits are referred to as landpre-pits (LPP). The land pre-pits represent sector addresses whichconstitute a recording timing signal.

During the recording mode of operation of the apparatus, data arerecorded on the optical disc 1. In general, the assignment of recordeddata portions to sectors of the optical disc 1 is designed so thatsector addresses (data addresses) in the recorded data portions will bein agreement with sector addresses (LPP addresses) represented by theland pre-pits. According to an example of data recording which providesagreement between data addresses and LPP addresses, data are reproducedfrom a DVD and are then recorded on a DVD-RW as they are. In this case,the data are continuously recorded on the DVD-RW so that data addressesand LPP addresses are in agreement with each other.

The recording mode of operation of the apparatus can be changed amongdifferent types including an RTR mode and a DVD-Video compatible mode.The user can select one of the RTR mode and the DVD-Video compatiblemode by operating the key input unit 10 to generate a mode selectionsignal. The mode selection signal is transmitted from the key input unit10 to the system controller 9. The system controller 9 changes therecording operation of the apparatus between the RTR mode and theDVD-Video compatible mode in response to the mode selection signal.Alternatively, the system controller 9 may change the recordingoperation of the apparatus between the RTR mode and the DVD-Videocompatible mode in response to a type of an input signal to be recorded.

FIG. 11 shows a flowchart of a portion of a program for the systemcontroller 9. The program portion in FIG. 11 relates to the recordingmode of operation of the apparatus. As shown in FIG. 11, a step S1 ofthe program portion decides whether or not the RTR recording mode isselected by referring to the mode selection signal. When it is decidedthat the RTR recording mode is selected, the program advances from thestep S1 to a step S2. On the other hand, when it is decided that the RTRrecording mode is not selected, the program advances from the step S1 toa step S3.

The step S2 records contents information on the data area DA of anoptical disc 1. In addition, the step S2 records lead-in information onthe first lead-in area LI1 of the optical disc 1. The lead-ininformation contains CSS-key information. The lead-in information may bedevoid of the CSS-key information.

The step S3 decides whether or not the DVD-Video-compatible recordingmode is selected by referring to the mode selection signal. When it isdecided that the DVD-Video-compatible recording mode is selected, theprogram advances from the step S3 to a step S4. On the other hand, whenit is decided that the DVD-Video-compatible recording mode is notselected, the program advances from the step S3 to another step-(notshown).

The step S4 records contents information on the data area DA of theoptical disc 1. In addition, the step S4 records lead-in information onthe second lead-in area LI2 except the pre-pit area PR of the opticaldisc 1. The recorded lead-in information is devoid of CSS-keyinformation. The steps S2 and S4 are followed by a common step (notshown).

In the case where the pre-pit area PR has an 8-Kbyte size correspondingto 4 sectors, lead-in information of 24 Kbytes (=32 Kbytes−8 Kbytes) isrecorded on the second lead-in area LI2 except the pre-pit area PR forone ECC block (32 Kbytes). On the other hand, in the case where thepre-pit area PR has a 32-Kbyte size, the recording of lead-ininformation on the second lead-in area LI2 is not executed for one ECCblock.

During the RTR recording mode of operation of the apparatus, contentsinformation and lead-in information are recorded on the optical disc 1on a real-time basis. The after-recording optical disc 1 is incompatiblewith a DVD-Video.

During the DVD-Video-compatible recording mode of operation of theapparatus, it is difficult to record complicatedly-edited contentsinformation on the optical disc 1 on a real-time basis. Theafter-recording optical disc 1 is compatible with a DVD-Video.Therefore, the after-recording optical disc 1 can be played back by acommercially-available DVD-Video player.

FIG. 12 shows a flowchart of a portion of a program for the systemcontroller 9. The program portion in FIG. 12 may replace the programportion in FIG. 11. As shown in FIG. 12, a step S11 of the programportion decides whether or not the DVD-Video-compatible recording modeis selected by referring to the mode selection signal. When it isdecided that the DVD-Video-compatible recording mode is selected, theprogram advances from the step S11 to a step S12. On the other hand,when it is decided that the DVD-Video-compatible recording mode is notselected, the program advances from the step S11 to a step S13.

The step S12 records contents information on the data area DA of anoptical disc 1. In addition, the step S12 records lead-in information onthe second lead-in area LI2 except the pre-pit area PR of the opticaldisc 1. The recorded lead-in information is devoid of CSS-keyinformation.

The step S13 decides whether or not the RTR recording mode is selectedby referring to the mode selection signal. When it is decided that theRTR recording mode is selected, the program advances from the step S13to a step S14. On the other hand, when it is decided that the RTRrecording mode is not selected, the program advances from the step S13to another step (not shown).

The step S14 records contents information on the data area DA of theoptical disc 1. In addition, the step S14 records lead-in information onthe first lead-in area LI1 of the optical disc 1. The lead-ininformation contains CSS-key information. The lead-in information may bedevoid of the CSS-key information. The steps S12 and S14 are followed bya common step (not shown).

An optical disc 1 played back by the apparatus can be changed among DVDinformation recording media including a DVD-Video, a DVD-RW version“1.0”, and a DVD-RW in the first embodiment of this invention. As viewedat physical radial positions in FIG. 1, the DVD-Video does not have afirst lead-in area LI. The DVD-Video has a second lead-in area LI2 whichstores lead-in information containing CSS-key information. The DVD-RWversion “1.0” has a first lead-in area LI1. The DVD-RW version “1.0”also has an unreadable lead-in area positionally corresponding to asecond lead-in area LI2. The DVD-RW in the first embodiment of thisinvention has a first lead-in area LI1 and a second lead-in area LI2which are readable. In the DVD-RW of the first embodiment of thisinvention, the first lead-in area LI1 stores first lead-in information,and the second lead-in area LI2 stores second lead-in informationcontaining copyright-protection-related information such as informationof a CSS key corresponding to a given value.

FIG. 13 shows a flowchart of a portion of the program for the systemcontroller 9. The program portion in FIG. 13 relates to the playbackmode of operation of the apparatus. As shown in FIG. 13, a step S5 ofthe program portion accesses lead-in information on the first lead-inarea LI1 of an optical disc 1.

A step S6 following the step S5 decides whether or not the lead-ininformation is valid as a media type by referring to flag information inthe lead-in information. When it is decided that the lead-in informationis valid, the program advances from the step S6 to a step S7. On theother hand, when it is decided that the lead-in information is notvalid, the program advances from the step S6 to a step S8. Also, when itis found that the lead-in information is absent from the first lead-inarea LI1, the program advances from the step S6 to the step S8.

The step S7 reproduces the lead-in information from the first lead-inarea LI1 of the optical disc 1. The reproduced lead-in informationcontains CSS-key information. The reproduced lead-in information may bedevoid of the CSS-key information. In addition, the step S7 reproducescontents information from the data area DA of the optical disc 1 inaccordance with the reproduced lead-in information. The reproduction ofthe contents information is implemented in, for example, an RR playbackmode.

The step S8 accesses lead-in information on the second lead-in area LI2of the optical disc 1. The step S8 decides whether or not the lead-ininformation is valid as a media type by referring to flag information inthe lead-in information. When it is decided that the lead-in informationis valid, the program advances from the step S8 to a step S9. On theother hand, when it is decided that the lead-in information is notvalid, the current execution cycle of the program portion ends.

The step S9 reproduces the lead-in information from the second lead-inarea LI2 of the optical disc 1. The reproduced lead-in informationcontains CSS-key information. In addition, the step S9 reproducescontents information from the data area DA of the optical disc 1 inaccordance with the reproduced lead-in information. The reproduction ofthe contents information is implemented in, for example, aDVD-Video-compatible playback mode. The step S9 may stop thereproduction of the contents information when the reproduced lead-ininformation and the apparatus are in a predetermined unacceptablerelation.

FIG. 14 shows a flowchart of a portion of a program for the systemcontroller 9. The program portion in FIG. 14 may replace the programportion in FIG. 13. As shown in FIG. 14, a step S15 of the programportion accesses lead-in information on the second lead-in area LI2 ofan optical disc 1.

A step S16 following the step S15 decides whether or not the lead-ininformation is valid as a media type by referring to flag information inthe lead-in information. When it is decided that the lead-in informationis valid, the program advances from the step S16 to a step S17. On theother hand, when it is decided that the lead-in information is notvalid, the program advances from the step S16 to a step S18.

The step S17 reproduces the lead-in information from the second lead-inarea LI2 of the optical disc 1. The reproduced lead-in informationcontains CSS-key information. In addition, the step S17 reproducescontents information from the data area DA of the optical disc 1 inaccordance with the reproduced lead-in information. The reproduction ofthe contents information is implemented in, for example, aDVD-Video-compatible playback mode.

The step S18 accesses lead-in information on the first lead-in area LI1of the optical disc 1. The step S18 decides whether or not the lead-ininformation is valid as a media type by referring to flag information inthe lead-in information. When it is decided that the lead-in informationis valid, the program advances from the step S18 to a step S19. On theother hand, when it is decided that the lead-in information is notvalid, the current execution cycle of the program portion ends. Also,when it is found that the lead-in information is absent from the firstlead-in area LI1, the current execution cycle of the program portionends.

The step S19 reproduces the lead-in information from the first lead-inarea LI1 of the optical disc 1. The reproduced lead-in informationcontains CSS-key information. The reproduced lead-in information may bedevoid of the CSS-key information. In addition, the step S19 reproducescontents information from the data area DA of the optical disc 1 inaccordance with the reproduced lead-in information. The reproduction ofthe contents information is implemented in, for example, an RTR playbackmode. The step S19 may stop the reproduction of the contents informationwhen the reproduced lead-in information and the apparatus are in apredetermined unacceptable relation.

In the information recording medium, 16 successive data sectors (32Kbytes) compose one ECC block which is a minimum unit of recording andreproducing data. Each data sector is composed of 26 sync frames towhich sync signals are added (see FIG. 4). The sync frames aresynchronized with a sync timing signal for recording, and with LPPaddresses. The DVD-RW has the additional feature that land pre-pitsrepresenting sector addresses are formed at given intervals along atrack.

As previously mentioned, the second lead-in area LI2 of the informationrecording medium or the DVD-RW contains the pre-pit area PR which storesthe copyright-protection-related information (the CSS-key information orthe copy guard information). According to a first example, the pre-pitarea PR occupies only 4 sectors in one ECC block. According to a secondexample, the pre-pit area PR fully occupies 16 sectors in one ECC block.

In the case where the pre-pit area PR occupies only 4 sectors in one ECCblock, the recording of data on the ECC block is implemented as follows.The ROM within the system controller 9 stores thecopyright-protection-related information same as that recorded on thepre-pit area PR of the information recording medium. The systemcontroller 9 reads out the copyright-protection-related information fromthe ROM. The system controller 9 uses the track buffer memory 14 via thesignal processor 5, and thereby combines thecopyright-protection-related information with data to be recorded on theECC block. The combining-resultant data are processed intoECC-signal-added data (PI/PO-signal-added data) for the ECC block. TheECC-signal-added data for the ECC block are referred to as the1-ECC-block data. With reference to FIG. 15, a first portion of the1-ECC-block data is recorded while the LPP-based recording timing signalis used as reference timings indicative of the boundaries betweensectors or the heads of sectors. The first portion extends from the headof the 1-ECC-block data to a point corresponding to the starting edge ofthe pre-pit area PR. At the timing corresponding to the starting edge ofthe pre-pit area PR and given by the LPP-based recording timing signal,the system controller 9 suspends the recording and changes the operationof the apparatus from the recording mode to the playback mode. Therecording continues to be suspended until the timing corresponding tothe ending edge of the pre-pit area PR and given by the LPP-basedrecording timing signal. As a result, a second portion of the1-ECC-block data which follows the first portion thereof is not recordedon the pre-pit area PR. Thus, the original copyright-protection-relatedinformation recorded on the pre-pit area PR is prevented from beingdamaged and contaminated by the phase change overwrite. At the timingcorresponding to the ending edge of the pre-pit area P, the systemcontroller 9 returns the operation of the apparatus to the recordingmode and restarts the recording. Therefore, a third portion of the1-ECC-block data is recorded while the LPP-based recording timing signalis used as reference timings indicative of the boundaries betweensectors or the heads of sectors. The third portion extends between apoint corresponding to the ending edge of the pre-pit area PR and theend of the 1-ECC-block data.

In the case where the pre-pit area PR fully occupies 16 sectors in oneECC block, the recording of data on the ECC block is not executed asshown in FIG. 16.

During the playback of the information recording medium (the DVD-RW) bya DVD-Video player, lead-in information is reproduced from the secondlead-in area LI2 of the information recording medium. The reproducedlead-in information contains CSS-key information. Then, contentsinformation is reproduced from the data area DA of the informationrecording medium in response to the reproduced lead-in information. Thereproduction of the contents information may be stopped when thereproduced lead-in information and the player are in a predeterminedunacceptable relation.

During the playback of the information recording medium (the DVD-RW) bythe apparatus in the second embodiment of this invention, first lead-ininformation is reproduced from the first lead-in area LI1 of theinformation recording medium. In the case where the first lead-ininformation is absent from the first lead-in area LI1 or flaginformation in the first lead-in information indicates that the firstlead-in information is invalid, second lead-in information is reproducedfrom the second lead-in area of the information recording medium. In thecase where the second lead-in information is required, the secondlead-in information is reproduced from the second lead-in area of theinformation recording medium. The second lead-in information containscopyright-protection-related information. Contents information isreproduced from the data area DA of the information recording medium inresponse to the reproduced second lead-in information. On the otherhand, in the case where the flag information in the first lead-ininformation indicates that the first lead-in information is valid, thecontents information is reproduced from the data area DA of theinformation recording medium in response to the reproduced first lead-ininformation.

When the pre-pit area PR occupies only 4 sectors in one ECC block (seeFIG. 15), the recorded data on the ECC block has two linkings or seams.During playback, the error correction process is able to successfullycorrect data errors which might be caused by the linkings since thenumber of the data errors is within the range of the ability to correcterrors. Thus, the original copyright-protection-related information canbe stably and accurately reproduced.

It is assumed that the information-recording medium (the DVD-RW) storesgiven CSS-key information in its pre-pit area PR, and contentsinformation scrambled according to a CSS is illegally recorded andcopied on the data area DA of the information recording medium. Usually,CSS-key information corresponding to the illegally-recorded contentsinformation is different from the given CSS-key information so that theillegally-copied contents information can not be descrambled duringplayback. Thus, the illegally-copied contents information can not bereproduced by a player such as a DVD-Video player. On the other hand,after unscrambled contents information (for example, personal contentsinformation) is recorded on the data area DA of the informationrecording medium, the contents information can be reproduced from theinformation recording medium by a DVD-Video player.

Other Embodiments

The DVD-Video in the first and second embodiments of this invention maybe replaced by a DVD-Audio. The DVD in the first and second embodimentsof this invention may be replaced by another high-density large-capacityrecording medium.

1-30. (canceled)
 31. A method of reproducing information from an information recording medium including a lead-in area, a first lead-in information area located in the lead-in area, a second lead-in information area located in the lead-in area, and a data area for storing information in prescribed error correction block units, wherein the first lead-in information area is an area which is subjected to recording in the prescribed error correction block units and on which lead-in information relating to the data area is to be recorded, and wherein the second lead-in information area is an area on which lead-in information relating to the data area is recorded, and the second lead-in information area includes pre-pits and has a boundary different from a boundary of an error correction block which occurs in cases where recording is done in the prescribed error correction block units, the method comprising the steps of: reading compressed data of a variable transfer rate from the data area in the information recording medium; decoding the read compressed data into decoded data; and temporarily storing the decoded data into a buffer to get continuously reproduced data.
 32. An apparatus for reproducing information from an information recording medium including a lead-in area, a first lead-in information area located in the lead-in area, a second lead-in information area located in the lead-in area, and a data area for storing information in prescribed error correction block units, wherein the first lead-in information area is an area which is subjected to recording in the prescribed error correction block units and on which lead-in information relating to the data area is to be recorded, and wherein the second lead-in information area is an area on which lead-in information relating to the data area is recorded, and the second lead-in information area includes pre-pits and has a boundary different from a boundary of an error correction block which occurs in cases where recording is done in the prescribed error correction block units, the apparatus comprising: first means for reading compressed data of a variable transfer rate from the data area in the information recording medium; second means for decoding the compressed data read by the first means into decoded data; and third means for temporarily storing the decoded data into a buffer to get continuously reproduced data. 